TY - JOUR
T1 - Upright posture increases oxyhemoglobin saturation in Peruvian highlanders
AU - Arias, Rafael S.
AU - Etienne, Branden
AU - Polotsky, Vsevolod Y.
AU - Checkley, William
AU - Schwartz, Alan R.
AU - Pham, Luu V.
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/8
Y1 - 2019/8
N2 - At high altitude, hypoxia amplifies oxyhemoglobin saturation (SPO2) swings with changes in respiratory mechanics. Our objective was to examine the effects of posture on SPO2 and determine predictors of postural SPO2 changes in highlanders. 50 native highlanders from Puno, Peru (3825 m) assumed supine and upright-seated postures, in rotating sequence, while undergoing continuous pulse-oximetry. We compared mean SpO2 in each posture with a paired t-test. We examined associations of BMI, age, sex and spirometry with postural SpO2 changes with mixed-effects linear regression. In highlanders, SpO2 was 84% in the supine posture and was 1.0% ± 1.1 (p < 0.0001) greater in the upright-seated posture. Greater postural changes in SpO2 were associated with older age (p = 0.01 for interaction) but not with sex, BMI, FVC or FEV1. In highlanders, SpO2 is higher in the upright-seated compared to supine posture, especially with older age. Because we generally sleep flat, posture may contribute significantly to highlanders’ hypoxemic burden during sleep. Postural intervention during sleep may mitigate nocturnal hypoxemia.
AB - At high altitude, hypoxia amplifies oxyhemoglobin saturation (SPO2) swings with changes in respiratory mechanics. Our objective was to examine the effects of posture on SPO2 and determine predictors of postural SPO2 changes in highlanders. 50 native highlanders from Puno, Peru (3825 m) assumed supine and upright-seated postures, in rotating sequence, while undergoing continuous pulse-oximetry. We compared mean SpO2 in each posture with a paired t-test. We examined associations of BMI, age, sex and spirometry with postural SpO2 changes with mixed-effects linear regression. In highlanders, SpO2 was 84% in the supine posture and was 1.0% ± 1.1 (p < 0.0001) greater in the upright-seated posture. Greater postural changes in SpO2 were associated with older age (p = 0.01 for interaction) but not with sex, BMI, FVC or FEV1. In highlanders, SpO2 is higher in the upright-seated compared to supine posture, especially with older age. Because we generally sleep flat, posture may contribute significantly to highlanders’ hypoxemic burden during sleep. Postural intervention during sleep may mitigate nocturnal hypoxemia.
KW - Altitude
KW - Andean
KW - Global health
KW - Hypoxia
UR - http://www.scopus.com/inward/record.url?scp=85066050412&partnerID=8YFLogxK
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U2 - 10.1016/j.resp.2019.04.015
DO - 10.1016/j.resp.2019.04.015
M3 - Article
C2 - 31048020
AN - SCOPUS:85066050412
SN - 1569-9048
VL - 266
SP - 138
EP - 143
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
ER -